1. Field of the Invention
The present invention relates to an apparatus and method for cleaning a semiconductor wafer with a cleaning solution.
2. Related Art
A single-wafer process, which involves cleaning a wafer by dropping a cleaning solution on a surface of the wafer while rotating the wafer, is often employed for a cleaning system in a process for manufacturing a semiconductor device.
A typical cleaning apparatus in such cleaning system, which cleans a wafer by disposing a wafer on a rotating table and dropping a cleaning solution on the wafer from a nozzle, is known in the art (see, for example, Japanese Patent Laid-Open No. 2001-176,831). In such type of cleaning apparatus, as shown in FIG. 7, dusts and/or accumulated materials remained on the surface of the wafer are removed by sweeping these dusts with the cleaning solution spreading via a centrifugal force that is created by the rotation of the wafer. In the cleaning apparatus described in Japanese Patent Laid-Open No. 2001-176,831, a cup member is provided so as to surround a radially outer circumference of the rotating table, and the cleaning solution scattering from the circumference of the wafer toward radial outer directions is collected.
In addition, other type of cleaning apparatus, in which a circumference of a wafer is supported by a plurality of roller, and is provided with a mask under the wafer, is proposed (see, for example, Japanese Patent Laid-Open No. 2002-246,364). In such cleaning apparatus, a gap is provided between the mask and a lower surface of the wafer to have a size of about 0.05 to 1.0 mm, and the cleaning solution is drawn into the gap by utilizing capillary phenomenon.
Nonetheless, since the cleaning solution is separated from the wafer and is scattered in the cleaning apparatus described in Japanese Patent Laid-Open No. 2001-176,831, no cleaning solution is supplied to the side edge of the wafer, such that a sufficient removal of dusts remained on the side surface of the wafer can not be achieved.
In addition, since the cleaning solution is drawn into the gap by utilizing capillary phenomenon in the cleaning apparatus described in Japanese Patent Laid-Open No. 2002-246,364, the cleaning solution cannot be sufficiently circulated across the wafer. More specifically, since a flow rate of the cleaning solution is extremely low, it is difficult to remove dusts on the side edge of the wafer, and thus an efficiency in the cleaning of the side edge of the wafer is extremely deteriorated.